LG-11454: Restore successful WebAuthn delete handling user events

[aduth]

🎫 Ticket

Relates to LG-11454 (originally #9674)

🛠 Summary of changes

Restores additional behaviors expected to occur after the successful deletion of a WebAuthn credential.

I noticed these after starting to put together the clean-up pull request to remove the old deletion routes, which implement these behaviors:

identity-idp/app/controllers/users/webauthn_setup_controller.rb

Lines 148 to 152 in 8558b0b

	create_user_event(:webauthn_key_removed)
	webauthn.destroy
	revoke_remember_device(current_user)
	event = PushNotification::RecoveryInformationChangedEvent.new(user: current_user)
	PushNotification::HttpPush.deliver(event)

📜 Testing Plan

Verify specs pass:

1. rspec spec/controllers/api/internal/two_factor_authentication/webauthn_controller_spec.rb spec/controllers/users/webauthn_controller_spec.rb

You can also verify that behaviors actually happen when deleting Face or Touch Unlock:

1. (Prerequisite) Have an account with Face or Touch Unlock configured
2. Go to http://localhost:3000
3. Sign in
4. From account dashboard, click "Manage" for your Face or Touch Unlock
5. Click "Delete"
6. Confirm prompt
7. In Rails console, verify user event: User.find_with_email('email@example.com').events.webauthn_key_removed
8. TBD how to verify RISC event (see Slack thread)
9. Sign out
10. Sign in
11. Observe that you're prompted to MFA

[aduth]

Separately, it might be worth thinking about extracting this behavior, since we're doing several things here, and we have the same code across basically all of MFAs... or at least I expect we intend to, but the RISC events aren't consistently implemented (even more justification to extract a common helper).

e.g.

module TwoFactorAuthenticatableMethods
  # ...
  def handle_valid_auth_method_removed(user_event:)
    create_user_event(user_event)
    revoke_remember_device(current_user)
    event = PushNotification::RecoveryInformationChangedEvent.new(user: current_user)
    PushNotification::HttpPush.deliver(event)
  end
end